RDSO (Indian Railways) Industrial Training Report

RDSO, Lucknow
Industrial Training Report
On
INDIAN RAILWAYS
Submitted in the partial fulfillment of the requirement for the award of degree of
Bachelors of Engineering
in
Electronics & Communication Engineering
Submitted by:
Name: NEHA
Roll no. : SG-14518
UNIVERSITY INSTITUTE OF ENGINEERING AND TECHNOLOGY
HOSHIARPUR, PUNJAB
Name and Location of Company: Research Designs & Standards Organisation,
Lucknow

Electronics & Communication
RDSO, LUCKNOW
ACKNOWLEDGEMENT
Summer training has an important role in exposing the real life situation in
an industry. It was a great experience for me to work on training at
RESEARCH DESIGNS & STANDARDS ORGANISATION, LUCKNOW
through which I could learn how to work in a professional environment.
Now I would like to thank the people who guided me and have been a
constant source of inspiration throughout the tenure of my summer training.
I am sincerely grateful to-
Shri. P.C. Yadav & Shri. Parmod Sahu- Power Supply Installation
Smt. Anuradha Srivastava & Shri. Dharmraj- OHE Design
Shri. S.K. Botke & Shri. Nihal Singh- Conductor & Tower Wagon
Shri. R.K. Pal & Shri. Ved Bhanu Arya- OHE Equipment
at RDSO, Lucknow who rendered me their valuable assistance, constant
encouragement and able guidance which made this training actually
possible.
I wish my deep sense of gratitude to my parents whose affectionate
guidance has enable me to complete the training successfully. I also wish
my deep sense of gratitude to Mr. Balwant Raj (Training Head), UIET
Hoshiarpur and other faculty members.
NEHA
B.E. (ECE)
SG-14518

RDSO, LUCKNOW
TABLE OF CONTENT
 Introduction to RDSO
 Supply System for Electric Locomotive
 Power Supply for Electric Traction
 Conductor & Tower Wagon
 OHE Equipment
 Pantograph
 Conclusion
 Reference

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INTRODUCTION TO RDSO
The first railways in India were built in 1853 and their subsequent continent-wide
development saw the appearance of various private railway companies and state-
owned railway systems. To enforce standardization and coordination between these
sometimes-disparate systems, the Central Standard Office (CSO) was established in
1930 to prepare designs, standards and specifications. However, before Indian
independence in 1947, most of the design and manufacturing of rolling stock and
infrastructure was entrusted to foreign consultants. With the subsequent phenomenal
increase in the nation's industrial and economic activity and rising demand for railway
transport, a new organization called the Railway Testing and Research Centre (RTRC)
was set up in1952 at Lucknow to test and conduct applied research for development of
railway rolling stock, permanent way etc. In 1957, the CSO and RTRC were integrated
as the Research Design and Standards Organisation (RDSO) under the Ministry of
Railways at Lucknow.
Functions
RDSO is the sole R&D organization of Indian Railways and functions as the technical
advisor and consultant to the Indian Railway Board, regional railways and rolling
stock works. Basically, its activities involve:
 Development of new and improved designs
 Development and adoption of new technologies for use on Indian Railways
 Development of standards for materials and products especially needed by
Indian Railways
 Technical investigation, statutory clearance, testing and provision of consulting
services
 Inspection of critical and safety items for rolling stock, locomotives, signals,
telecommunications equipment, and track
RDSO also offers international consultancy services on design, testing and inspection
of railway equipment as well as surveys for construction of new lines. Consultancy
services have been provided to various countries such as Iraq, Sri Lanka, South Korea,
Zambia, Egypt, Nigeria, Saudi Arabia, etc.

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ZONES IN INDIAN RAILWAY
The Indian Railways is divided into zones, which are further sub-divided into divisions,
each having a divisional headquarters. There are a total of sixty-nine divisions. Each of
the divisions is headed by a Divisional Railway Manager (DRM) who reports to the
General Manager (GM) of the zone. A DRM can be appointed from any services of
Indian railway, Indian Administrative Service (IAS) and Indian Revenue Service (IRS)
for the tenure of 3 years but it can be exceeded on the recommendation of Railway
Board. Divisional officers heading all departments viz. engineering, mechanical,
electrical, signal and telecommunication, accounts, personnel, operating, commercial,
safety, medical, security branches report to the Divisional Railway Manager. The DRM
is assisted by one or two Additional Divisional Railway Managers (ADRM) in the
working of the division. There are seventeen main division in Indian railway listed
below….
1. Central railway-CR-Mumbai
2. East central railway-ECR-Hajipur
3. East coach railway-ECoR-Bhubaneswar
4. Eastern railway-ER-Kolkata
5. North central railway-NCR-Allahabad
6. North eastern railway-NER-Gorakhpur
7. North western railway-NWR-Jaipur
8. North east frontier-NFR-Guwahati
9. Northern railway-NR-Delhi
10. South central –SCR-Secunderabad.
11. South eastern-SER-Kolkata
12. South western –SWR-Hubli
13. Southern railway-SR-Chennai
14. South east central-SECR-Bilaspur
15. West central railway-WCR-Jabalpur
16. Western railway-WR-Mumbai
17. Kolkata Metro-Kolkata

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ELECTRIC LOCOMOTIVE
An electric locomotive is a locomotive powered by electricity from an external source.
Sources include overhead lines, third rail, or an on-board electricity storage device such
as a battery, flywheel system, or fuel cell. One advantage of electrification is the lack of
pollution from the locomotives themselves. Electrification also results in higher
performance, lower maintenance costs, and lower energy costs for electric locomotives.
Power plants, even if they burn fossil fuels, are far cleaner than mobile sources such as
locomotive engines. Also the power for electric locomotives can come from clean and/or
renewable including geothermal power, hydroelectric power; nuclear power, solar
power, and wind Electric locomotives are also quiet compared to diesel locomotives
since there is no engine and exhaust noise and less mechanical noise. The lack of
reciprocating parts means that electric locomotives are easier on the track, reducing
track maintenance. Power plant capacity is far greater than what any individual
locomotive uses, so electric locomotives can have a higher power output than diesel
locomotives and they can produce even higher short-term surge power for fast
acceleration. Electric locomotives are ideal for commuter rail service with frequent
stops. They are used on high-speed lines, such as ICE in Germany, Acela in the US,
Shinkansen in Japan and TGV in France. Electric locomotives are also used on freight
routes that have a consistently high traffic volume, or in areas with advanced rail
networks. Electric locomotives benefit from the high efficiency of electric motors, often
above 90%.Additional efficiency can be gained from regenerative braking, which allows
kinetic energy to be recovered during braking to put some power back on the line.
Newer electric locomotives use AC motor-inverter drive systems that provide for
regenerative braking.

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SUPPLY SYSTEMS FOR ELECTRIC LOCO
Indian Railway has adopted 25 KV industrial frequency (50 Hz) A.C supply system for traction
purposes. The power supplies are derived from 220 KV / 132 KV 3 phase transmission system from
the various grids. The basic arrangement constitutes incoming supply to Railway traction substation at
a voltage level of 220 KV / 132 KV, which normally feeds power along the track for 35-40 Km
.Adjacent traction substation are fed from different phases in rotation in order to balance the 3 phase
load in its entirety. Neutral sections are provided in between two adjacent substations to prevent the
bridging of different phases while passing the electric locomotive. Level of voltage is
reduced to 25 KV for the end use of locomotives by 21.6 MVA signal phase power
transformers placed at traction sub stations which are located at every 30-35 Kms
distance along the track.

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SINGLE PHASE SUBSTATION
A) INTRODUCTION
The single phase 50 Hz power for the electric traction is obtained from
220/132/110/66KV Extra High Voltage 3 phase grid system through step down single
phase transformers. For this purpose duplicate feeders comprising of only 2 phases are
run from the nearest sub-station of the Supply Authority to the traction substation. The
25 kV single phase conventional systems as adopted on Indian Railways have been
described in this report.
On the secondary side one transformer circuit breaker and one feeder circuit breaker
are installed with associated double pole isolator the bus bar connections being such
that full flexibility of operation is assured. The traction substation is designed for remote
operation. The facilities exist to change over from one feeder to the other by means of
isolator/bus coupler. One end of the secondary winding of the transformer is solidly
earthed at the substation and is connected to track/return feeder through buried rail.

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B) TRACTION TRANSFORMER
The traction transformer is a single phase transformer rated as under.
 Range Available: 5, 10, 25 & 50 KVA 25 KV I 240V,
50 Hz. Single phase, oil filled
 Design: According to IS & RDSO specifications.
 RDSO Spec No.: ETI/PSI/15(08/2003)
 Approval Agency: RDSO, CORE
 Type Tested: At CPRI & ERDA
 Used at: 220/25 KV, 132/25 KV, 110/25 KV &
66/25 KV
Railway Traction Substations, Switching stations, and other outdoor locations. The ATs
are suitable for pole mounting along with the Railway Track for supply of power to
electric signaling and or substation/switching station loads.
C) CIRCUIT BREAKER
The circuit breaker is a device which breaks the circuit automatic under faulty
condition and protects the substation equipment. The following types of circuit breakers
and interrupters are now in use for traction substation:
Circuit Breakers
a) 220/132/110/66 kV, Double pole: SF6 type
b) 25 kV Single Pole: SF6 type Vacuum type
c) Interrupters: SF6 Vacuum type
D) ISOLATOR
The isolator is a switch which used for isolate the circuit during maintenance and fault
condition. It always operates at no load condition.
Single & Double Pole 25 KV Isolators
 Range Available: 1250 Amp, 1600 Amp &
3150 Amp, 33 KV Class
 Design: As per latest IS & ROSO specifications.
 ROSO spec: ETI/OHE/16(01/94) with slip no. 1
(June2000)
 Approval agency: RDSO & CORE
 Type Test: CPRI & ERDA, Vadodra
 Used At : Section and paralleling post &
sub sectioning & paralleling post,
Feeding post &Traction sub-station

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Overview Of Traction Offerings
[1] Traction transformer
[2] Traction converter
[3] Traction control
[4] Train Control and Monitoring System
[5] Traction motor
[6] Diesel engine generator
[7] Auxiliary converter
[8] Battery charger
[9] Energy storage

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POWER SUPPLY IN ELECTRIC TRACTION
Power Supply
25 kV, AC, 50 Hz single phase power supply for electric traction is derived from the grid
of State Electricity Boards through traction sub-stations located along the route of the
electrified sections at distance of 35 to 50 km apart. The distance between adjacent
substations may however be even less depending on intensity of traffic and load of
trains. At present there are broadly four different arrangements in existence as under
1. The Supply Authorities supply power at 220/132/110/66 kV Extra High Voltage
(EHV) at each traction substation which is owned, installed, operated and
maintained by the Railways.
2. The Railway receives 3-phase power supply from the supply Authority at a single
point near the grid substation from where the Railway runs its own transmission
lines providing its own traction sub-stations.

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3. All EHV and equipment is owned, installed, operated and maintained by the
Supply Authority 25 kV traction substation along with feeder circuit breakers are
owned, installed, operated and maintained by the Railway.
4. Traction substation and power supply to OHE is monitored and controlled by
means of Supervisory Control And Data Acquisition (SCADA) system through
remote control centre by traction controller (TPC).
Duplicate Supply
1. Figure shows schematically the arrangement at a typical traction substation.
2. To ensure continuity of supply under all conditions, the high voltage feed to the
traction substations is invariably arranged wither from two sources of power or by
a double transmission line, so that if one source fails the other remains in
service. Suitable protective equipment is installed at the substations to ensure
rapid isolation of any fault in transmission lines and substation equipment, so that
the power supply for electric traction is maintained under all conditions.
3. At each traction substation, normally two single phase transformers are installed;
one which is in service and the other is 100% stand by. The present standard
capacity is 21.6 MVA (ONAN)/30.2 MVA (ONAF).
However transformers of capacity 13.5 MVA (ONAN)/10.8 MVA (ONAN) have also been
used at many of the substations. These transformers step down the grid voltage to 25
kV for feeding the traction overhead equipment (OHE). 25 kV feeders carry the power
from the substations to feeding posts located near the tracks. Each feeder is controlled
by a single pole circuit breaker equipped with protective devices.

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TYPICAL SCHEMATIC OF TRACTION POWER
SUPPLY FEEDING ARRANGEMENT

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25 kV Supply at Traction Substations
1. On the secondary side one transformer circuit breaker and one feeder circuit
breaker are installed with associated double pole isolator the bus bar
connections being such that full flexibility of operation is assured.
2. The traction substation is designed for remote operation.
3. The facilities exist to change over from one feeder to the other by means of
isolator/bus coupler.
4. One end of the secondary winding of the transformer is solidly earthed at the
substation and is connected to track/return feeder through buried rail.
Feeding and Sectioning Arrangements
1. The generation and transmission systems of Supply Authorities are 3 phase
systems. The single phase traction load causes unbalance in the supply system.
The unbalance has undesirable effects on the generators of the supply
Authorities and equipment of other consumers. If its value becomes excessive.
2. The permissible voltage unbalance at the point of common coupling on the grid
supply system should not exceed the following limits:-
Voltage unbalance (%)
Instantaneous 5
2 hours 3
Continuous 2
3. To keep the unbalance on the 3 phase grid system within the above limits, power
for ac single phase traction is tapped off the grid system across the different
phases at adjacent substations in cyclic order.
4. Thus it becomes necessary to separate electrically the overhead equipment
systems fed by adjacent substations. This is done by providing a ‘Neutral
Section’ between two substations on the overhead equipment to ensure that the

RDSO, Lucknow 15
two phases are not bridged by the pantographs of passing electric
locomotives/EMUs.
5. To ensure rapid isolation of faults on the OHE and to facilitate maintenance work,
the OHE is sectioned at intervals of 10 to 15 km along the route. At each such
point a ‘switching station interrupters, usually rated at 600 A are provided. The
shortest section of the OHE which can be isolated by opening interrupters alone
is called a ‘subsectors’. Each sub-sector is further sub-divided into smaller
‘elementary sections’ by provision of off-load type manually operated isolator
switches.
6. At some stations with large yards, alternate feeding arrangements are provided
so that the power for feeding and yards may be drawn from alternate routes.
Normally the switch is locked in one position, being changed to the other when
required after taking necessary precautions.
7. To meet requirements at electric loco running sheds, isolators with an earthing
device in the ’off’ position is provided. At watering stations manually operated
interrupters and isolators with earthing heels are provided to enable switching off
of the power supply locally and earthing the OHE to enable working on roofs of
rolling stock.
Feeding Post (FP)
Each feeder supplies the OHE on one side of the feeding post through interrupters
controlling supply to the individual lines. Thus, for a two track line, there will be four
interrupters at each feeding post.
Sectioning and Paralleling Post (SP)
These posts are situated approximately midway between feeding posts marking the
demarcating point of two zones fed from different phases from adjacent substations. At
these posts, a neutral section is provided to make it impossible for the pantograph of an
electric locomotive of EMU train to bridge the different phases of 25 kV supply while
passing from the zone fed from one substation to the next one. Since the neutral section
remains ‘dead’ warning boards are provided in advance to warn and remind the Driver

RDSO, Lucknow 16
of an approaching electric locomotive /EMU to open locomotive circuit breaker (DJ)
before approaching ‘neutral section’. to coast through it and then switch ‘on’ on the
other side. Special care is taken in fixing the location of neutral sections on level tangent
tracks far away from signals level crossing gates etc to ensure that the train coasts
through the neutral section at a sufficiently high speed to obviate the possibility of its
stopping and getting stuck within the neutral section. A paralleling interrupter is provided
at each ‘SP’ to parallel the OHE of the up and down tracks of a double track section
‘bridging interrupters’ are also provided to permit one feeding post to feed beyond the
sectioning post upto the next FP if its 25kV supply is interrupted for some reasons
These bridging interrupters are normally kept open and should only be closed after
taking special precautions as detailed in these rules.
Sub-Sectioning and Paralleling Post (SSP)
One or more SSPs are provided between each FP and adjacent SP depending upon
the distance between them. In a double track section. Normally three interrupters are
provided at each SSP i.e. two connecting the adjacent subsectors of up and down
tracks and one for paralling the up and down tracks.
Sub-Sectioning Post (SS)
These are provided only occasionally. These are similar to SSPs with provision for
sectioning of the OHE but not paralleling.
DESIGN ASPECTS OF TRACTION SUBSTATION
Spacing and Location
The sub-station spacing largely depends upon the permissible voltage drop at the
farthest end, which in turn depends upon various factors such as the traffic to be
moved, anticipated traffic in the future and gradients of the section to be electrified. The
voltage drop at the farthest end is calculated both for normal and extended feed
conditions on the basis of given combination of trains on UP & DOWN tracks, loads and

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specified speeds, track parameters of the section on the assumed length of the feed
zone. The calculations are repeated for different assumed lengths of feed zone and it is
ensured that the voltage at the farthest end is within the permissible limits.
In Planning the requirement of traction sub-station and its location on any section for
track electrification, the factor to be kept in mind may be summarized as given below:-
• Availability of adequate and reliable power supply lines. The transmission lines should
be as close as possible to the Rly lines.
• Willingness of electric supply authorities to extend their HV transmission lines to feed
the railway traction loads.
• Settlement of tariff rates.
• Traffic to be handled in the section.
• Gradients of the section.
• Anticipated traffic in the future.
• Single or double line section.
• Characteristics of the locomotive and speed etc.
• Allowable permissible voltage drop at the farthest end.
• Strength of the system to permit the voltage and current unbalance caused by the
traction single phase loads.
• Suitability of standard equipments.

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• The load is within the standard ratings of the transformer and other equipment under
normal and extended feed conditions.
• Availability of reasonably good leveled land as near to Rly track as possible.
• Location should be away from the dumping yards.
• Location of sub-station should not be less than 3 km from the airport.
• Provision of siding track for loading and unloading of heavy equipments.
• Location should be close to main Rly. Station where inspection staff can reach the
spot in the shortest time
On an average the spacing between the successive sub-station as adopted in earlier
electrification schemes was about 50 to 80 km, but with the interlocution of heavy haul
trains and increased passenger and goods traffic the spacing has been reduced to 40 to
60 km. only. On high density routes it may reduce further by converting existing SP into
TSS and SSP into SP.
TRACTION POWER SUPPLY SYSTEM
1. Before going into details of design aspects of various substation equipments, we
may briefly discuss the power supply system adopted for feeding the traction
substations.
2. Indian Rlys. purchase electric power from various state electricity boards and as
well as from other electric utilities through their regional grids at different voltage,
normally 220/132/110/66 kV. The incoming supply is stepped down to 25 kv. a.c.
with the help of step down transformer. The primary winding of the transformer is
connected across two phases of the three phase effectively earthed system and
one terminal of the 25 kV. Secondary winding is connected to the overhead
equipment (OHE) and other terminal of the 25 kV. Secondary winding is solidly
earthed and connected to the running rails. The load current flows through the
OHE to the locomotive and return through the rails and earth to the traction sub-
station.

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The substations are provided as close to the railway traction as possible at intervals
varying from 40 to 60 km depending upon the traffic density and track conditions. In the
initial stages of the AC electrification schemes, traction substations were owned and
maintained by electric supply authorities. But later on in the late sixties Indian Railways
started purchasing bulk power at 220 or 132 or 110 or 66 kV at a single point and run
their own transmission lines and installed, operated and maintained their own
substations.
3. In addition to two transformer circuit breakers, which are provided each on
primary and secondary side of the traction transformer, the output from the
transformer is fed to the overhead equipment on one side of the substation
through feeder circuit breakers and two interrupters provided at each line. The
transformer breaker acts as a back up to the feeder breaker. The feeder breaker
performs the usual duties of breaking the circuit under the normal and abnormal
conditions according to situation. The interrupter is also a type of circuit breaker,
but it is non-automatic i.e. it is not called upon to trip under fault conditions. It is
capable to carry the normal rated current and through fault currents. It performs
the duty of breaking the load current and is also called a load switch. All the

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breakers and interrupters are outdoor type and remote controlled from Central
Control Room generally situated at the Railways Divisional Headquarters.
4. Typical layout of traction substation is shown in figure: Each traction
substation is provided with two transformers. Only one transformer feeds the
traction over head equipment on either side of traction substation through the two
feeder circuit breakers. For protection, in all six circuit breakers are provided at
each traction substation out of which two are installed on the primary side and
two on the secondary side of the transformer. These breakers are known as
transformer breakers and act as back up protection to the feeder circuit breakers.
Two feeder circuit breakers control the supply to the overhead equipment. In the
event of any fault on the OHE, the feeder circuit breaker will trip and clear the
fault. The interrupter, load switch controls supply for each track.
5. Approximately midway between two adjacent substations, a dead zone known as
‘neutral section’ or phase break is provided to separate two different phases. The
section between the substation and the neutral section is called sector which is
further subdivided into subsectors by a set of interrupters located at sub
sectioning posts situated at intervals of 10 to 15 km. To reduce the voltage drop
along the line, both the lines in a double track section are paralleled at each sub
sectioning post and sectioning post with the help of a paralleling interrupter at
each post. At each sectioning post, a bridging interrupter with an under voltage
relay is provided at each line which enables the extension of feed from a
substation to the section fed by an adjacent substation, in case of an emergency
caused by failure of the adjacent substation.

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CONDUCTOR & TOWER WAGON
8 Wheeler Diesel Electric Tower Car (DETC) is self- propelled 4 axle bidirectional
vehicles with driving cabins at both ends. It is meant for periodical inspection, patrolling
and maintenance of traction over head equipments, attending to sites of break- downs,
restoration of damaged OHE equipments etc. It is also used to erect mast and stringing
of one tension length (1.6 Km) of catenary and contact wire on broad gauge electrified
routes of Indian Railway. The main traction alternator is self regulating brushless three
phase synchronous machine with built in exciter system. The alternator is coupled
directly with the main shaft of the 700HP diesel engine. The traction alternator out put
650V AC, 3 phase, 120 Hz is fed to the main rectifier unit with three bridge configuration
of capsule type high capacity diodes. Rectifier unit is mounted on under frame of the
tower wagon. The rectified DC output is fed to the four traction motors connected in
permanent parallel arrangement through motor overload relay and line contactors on
positive side and negative contactors on negative side. The traction motors are series
wound and rated 167 kW, 535 Volt, 340 Amps and 1260 RPM with nose suspension
mounting arrangement. Each motor drives each axle independently. Motor cut out
switch facilitates the isolation of maximum up to two motors in the event of fault on

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traction motors. The tower wagon include a roof top elevating platform, engine cooling
system, air brake system and driving cabs at both ends. Elevating platform with
swiveling capability of 90 degree on each side provides access to the OHE. The
satisfactory up keep of tower wagon is of utmost importance. It is the direct
responsibility of tower wagon in-charge to ensure that the tower wagon is maintained
satisfactorily and is available always for attending OHE maintenance and for use in the
event of OHE breakdown.
GENERAL DATA

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TECHNICAL DETAILS
DIESEL ENGINE
The alternator is coupled directly with the main shaft of the diesel engine. The diesel
engine is self contained with engine mounted 30 CFM air compressor, exhaust
manifold, PT fuel pump, lubricating oil pump, starter motor, radiators for cooling system
with hydraulic fan drive arrangements, sensors, gauges and instruments etc.
TRACTION ALTERNATOR
Traction alternator is self regulating brushless three phase synchronous machine with
built in exciter system. The alternator is coupled directly with the main shaft of the diesel
engine.

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TRACTION MOTOR
The traction motor is a four pole self ventilated machine. The motor is mounted on the
axle with the help of sleeve suspension bearings. The transverse movement is limited
by the flanges of the axle suspension bearings.
POWER RECTIFIER
The power rectifier equipment has been designed
for Diesel Electric Tower Wagon for running on
broad gauge. It consists of capsule diodes, relays,
micro-switches, current transformers and potential
transformers etc. The rectifier unit can withstand
shocks and actions encountered in service.
It rectifies the three phase variable voltage, variable frequency alternator output
voltage into a smooth DC voltage, for driving four traction motors connected in parallel
across the rectifier.

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AUXILIARY ALTERNATOR
The auxiliary alternator is designed for power supply with drive from pulley mounted on
the extension of the shaft of the traction alternator in the tower wagon. It consists of a
brushless inductor type and a completely static regulator rectifier unit. The alternator is
completely devoid of any type of moving coils or sliding contacts.
The auxiliary alternator is used for charging the battery of 120 AH provided in the tower
wagon and for supplying the loads on the tower wagon like lights, blowers and the
control system etc.
HYDRAULIC TELESCOPIC LIFTING AND SWIVELING
PLATFORM
Hydraulic telescopic lifting and swiveling
platform is fitted on tower wagon for periodic
inspection, patrolling and maintenance of
overhead equipment on electrified sections.

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The platform has simplified design having hydraulic operation for lifting and lowering.
Swiveling of the working platform is affected through a separate electrical motor,
gearbox, gear and pinion. Lifting, lowering and swiveling are controlled electrically from
a control panel fixed on the outer boom or from push button pendent hooked onto the
working platform.
BATTERY
There are two types of batteries
 Starter battery
 Control supply battery
Starter Battery
A starter battery, 24 V, 290Ah, is provided for starting the diesel engine. The battery can
withstand a maximum of six cranking at 10 second intervals. In addition the battery also
feeds for 24 Volts, 70 watts, search and FOG lights provided in the front wall of tower
wagon.

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Control Supply Battery
A constant voltage of 115 volts (± 5%) dc at a maximum load current 74 Amps is utilized
for charging control battery of 120 Ah capacity, control supply for motoring, coach lights,
fans, cab head, tail, marker and flasher lights etc.
DG SET
7.5 KVA DG set
7.5 KVA DG set with 3 phase 415 volts AC output is provided for drilling machine in
work shop room and supply for control panel for lifting, lowering and swiveling of
platform with hydraulically operated ram for attending maintenance and breakdown
works at site.

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2 KVA DG set
A small 2 KVA DG set with single phase 230 volts AC
output is also provided for four 500 watts, halogen
flood lights on platform of hydraulically operated ram
for breakdown services at night. One number of
battery charging socket with DC protector is provided
for supplying 12V, 10A Dc supply for charging the
battery.
OVERHEAD EQUIPMENT (OHE)
The electrical conductors over the track together with their associated fittings, insulators
and other attachments by means of which they are suspended and registered in
position. All overhead electrical equipment, distribution lines, transmission lines and
feeders may be collectively referred to as overhead lines.

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Cantilever Assembly
It is an insulated swiveling type structural member, comprising of different sizes of steel
tubes, to support and to keep the overhead Catenary system in position so as to
facilitate current collection by the pantograph at all speed without infringing the
structural members. It consists of the following structural members.
Stay arm
It comprises of dia. 28.4/33.7 mm (Small) size tube and an adjuster at the end to keep
the bracket tube in position. It is insulated from mast by stay arm insulator.
Register Arm
It comprises of dia. 28.4 x 33.7 mm tube to register the contact wire in the desired
position with the help of steady arm.
Steady arm assembly
It is 32 x 31 mm BFB section made of aluminum alloy to register the contact wire to the
required stagger and to take the push up of contact wire. It is always in tension.
Dropper
A fitting used in overhead equipment construction for supporting the contact wire from
Catenary.
Height of contact wire
The distance from rail level to the underside of contact wire.
Jumper
A conductor or an arrangement of conductors for electrical continuity not under tension,
which forms electrical connection between two conductors or equipments.
Mast
A single vertical post embedded in the foundation or otherwise rigidly fixed in vertical
position to support the overhead equipment with cantilever assembly. It may be rolled
section or fabricated. The uprights of portals and TTCs are also called masts.

RDSO, Lucknow 30
Note: Pre-stressed concrete spun poles for traction overhead equipment are under
development.
Bracket tube
It comprises of dia. 40/49 mm (large) or dia. 30/38 mm (standard) bracket tube and
insulated by bracket insulator. Catenary is supported form this member by Catenary
suspension bracket and Catenary suspension clamp.
Terminology about separations
a. Stagger: Stagger of the contact wire is the horizontal distance of the contact wire
from the vertical plane through the centre of track.
b. Span: The distance between the centre line of the adjacent supporting masts for
overhead equipment/lines. Clear span in case of portal structure, is the distance
between the inner faces of portal uprights.
c. Setting Distance: The horizontal distance from the nearest face of traction mast to the
centre line of the track.
d. Suspension Distance: The horizontal distance from the centre of the eye of Catenary
suspension bracket to the face of the mast for a single cantilever assembly or the face
of cross arm channel in case of multiple cantilever assembly.
e. Electrical Clearance: The distance in air between live equipment and the nearest
earthed part.
f. Encumbrance: The axial distance on vertical plane between the Catenary and the
contact wire at support.
Crossings
The electrically live member / conductor passing over another electrically live member /
conductor, without physical contact.
a. Power line crossing: An electrical overhead transmission or distribution line or
underground cable placed across railway tracks whether electrified or not for
transmission of electrical energy.
b. Crossing OHE: Crossing of two conductors of OHE crossing without physical
contact.

RDSO, Lucknow 31
Feeder
A conductor connecting a
(a) Substation with a feeding post, or
(b) Feeding post with the OHE.
Interrupter
It is a single phase Vacuum SF6 / oil circuit breaker used as load switch to close the
circuit on fault but does not open on fault. It is operated either by remote control or
manually at site.
Different methods of connection of interrupters are:
a. Bridging Interrupter: An interrupter which is provided at the neutral section to
extend the feed from one substation to the overhead equipment normally fed by
the other substation in emergencies or when the latter is out of use. This
normally remains in the open position.
b. Sectioning Interrupter: An interrupter which connects adjacent sub-sectors
together to maintain continuity of supply. This normally remains in closed
position.
c. Paralleling Interrupter: An interrupter which connects overhead equipments of
two different tracks. This normally remains in closed position to reduce the
voltage drop.
Any fixed structure provided over the track. The prescribed clearance is normally
provided as laid down in the Schedule of Dimensions for unrestricted movement of
rolling stock.
Regulating Equipment
A device for maintaining the tension of OHE conductors constant under all ambient
temperature conditions.
Return conductor
A conductor which carries return current from the tracks to the sub-station in the booster
transformer system.

RDSO, Lucknow 32
Portals
On multiple track sections, where adequate track centres are not available and tracks
cannot be slewed, ports are used. Each portal consists of two fabricated uprights and
one fabricated boom consisting of with or without one central piece and two end pieces.
PANTOGRAPH
INTRODUCTION
“A collapsible device mounted on and insulated from the roof of an electric engine or
motor coach for collecting current from the overhead equipment is known as
Pantograph.”
When the pantograph of a locomotive passes from one track to another along a cross
over, current collection changes from one OHE to another. The runners do have the
overlap so that there may not be any sparking during change over.

RDSO, Lucknow 33
PANTOGRAPH OPERATION
a. The pantograph mounted on the roof of the OHE Inspection Car is electrically
bonded to the under frame by means of a cable connection. This cable
connection should be checked before starting any operation for checking and
adjustment of OHE.
b. The pantograph should normally be kept in the fully lowered position and
clamped securely by means of the special clamp provided for the purpose. No
string, cord etc shall be used for this purpose.
c. Before any person goes up to the roof of the OHE Inspection Car for
commencing Inspection and adjustment, the section of the OHE concerned shall
be made dead and earthed on either sides. Additional earths shall be provided
where necessary. After earthing the OHE, an additional earth shall be provided
near the OHE Inspection Car on the OHE of the track on which it is standing. An
authorized person not lower in rank than a linesman shall then go up on the roof
and remove the clamps to release the pantograph.
d. Under no circumstances should the OHE Inspection Car be worked with the
pantograph raised without an earth on either side of it on the section of the OHE
in which it is to be worked.
e. In order to ensure that the pantograph does not enter a section where the OHE is
live the OHE Inspection Car shall be protected on both the sides with banner

RDSO, Lucknow 34
flags and other signal flags. The driver shall always stop the OHE Inspection Car
ahead of all turn outs, crossovers, insulated overlaps and section insulators first
and then proceed only after ensuring that the section ahead is dead and earthed.
Banner flags then are removed for the purpose of admitting the OHE Inspection
Car into the section ahead.
f. At the end of the inspection and checking, the pantograph shall be lowered and
clamped by an authorized person not lower in rank than a linesman working on
the roof after earthing the OHE of the track on which the OHE Inspection Car
operating. The earths on the OHE near the OHE Inspection Car shall then be
removed after all persons working on the roof have come down.
PANTOGRAPH ENTANGLEMENT
Introduction
Electric locomotive gets power from overhead contact wire through pantograph. For
smooth operation of locomotive, the movement of pantograph should be even and
unobstructed on the contact wire, when any part of pantograph comes in between
overhead wires or vice versa, panto entanglement takes place.

RDSO, Lucknow 35
Causes of Pantograph Entanglement
Panto entanglement causes damage to pantograph and overhead equipment resulting
in dislocation of Electric Traction traffic.
Pantograph entanglement occurs due to following reasons-
a. OHE defects
b. Pantograph defects
OHE Defects: Damaged OHE components such as insulators, cantilever tubes,
jumpers, droppers etc. may foul with the movement of the pantograph and result in
entanglement. The OHE defects that can cause panto entanglement are-
 Improper adjustment of crossover and turn-out and
 Malfunctioning of ATD.
 Damage of OHE components.
 Apart from this if locomotive goes in unwired section by mistake it may
damage both the panto and 9 tonne insulators.
To avoid them-
 Check insulators, droppers and other OHE component periodically for any
cracks.
 Ensure provision of C jumpers to avoid dropper failure.
 Ensure provision of double PG clamps on G jumpers and feeder wire locations.
Auto Tensioning Device
ATD keeps OHE in correct tension. If ATD drum is not moving freely, the OHE tension
will not remain correct. This will cause sag in OHE at higher temperature, any sag in
OHE is prone to panto entanglement when pantograph is moving at high speed.
Ensuring free movement of ATD and providing 100 mm sleeve on anti falling device
rods in short tension length prevents sagging of OHE. Contact wire consists of joints
within the running length. These joints are made during manufacturing. Their failure
results in snapping of contact wire. If a locomotive is moving in the same zone where

RDSO, Lucknow 36
such a snapping takes place panto entanglement will result. Therefore it is necessary to
check frequently all the joints, especially those in the polluted area where they are
prone to more failures. Provide slice at such joints which may work out to avoid
snapping.
Pantograph Defects: The defects of pantograph which cause panto entanglement are-
 Spring box failures
 Improper static force on OHE
 Missing pins and fasteners
 Cracks in mechanical parts and
 Improper leveling of pan.
These defects can be minimizes by-
 Checking regularly the conditions of cracked OHE fittings
 Properly fastening of pantograph wearing strips
 Checking availability of split pins
 Investigating broken parts of the pantograph.

RDSO, Lucknow 37
CONCLUSIONS
POWER SUPPLY INSTALLATIONS
 25 kV AC, 50 Hz single phase power supply for electric traction is derived from
the grid of State Electricity Boards through traction sub-stations.
 25 kV feeders carry the power from the substations to feeding posts located near
the tracks.
 The permissible variation of the bus bar voltage on the bus bars at the grid
substations is +10% and 5%.
 Feeding Post is a supply post where the incoming 25 kV feeder lines from
substation are terminated and connected to the overhead equipment through
interrupters.
 Sectioning and Paralleling Post is the supply control post situated mid-way
between two feeding posts at the neutral section and provided with bridging and
paralleling interrupters. is the supply control post situated mid-way between two
feeding posts at the neutral section and provided with bridging and paralleling
interrupters.
 Sub-Sectioning and Paralleling Post is a supply control post where sectioning
and paralleling interrupters are provided.
 Sub-Sectioning Post is a supply control post where a sectioning interrupter is
provided.

RDSO, Lucknow 38
PRINCIPLES FOR LAYOUT PLANS AND SECTIONING
DIAGRAMS FOR 25 KV A.C TRACTION
 These principles for preparation, checking and finalization of overhead
equipment layout plans, have been framed for standardization and guidance
of Railways / Railway Electrification Projects.
 The electrical conductors over the track together with their associated fittings,
insulators and other attachments by means of which they are suspended and
registered in position is known as Over Head Equipements.
PANTOGRAPH
 A collapsible device mounted on and insulated from the roof of an electric
engine or motor coach for collecting current from the overhead equipment is
known as Pantograph.
 When any part of pantograph comes in between overhead wires or vice
versa, panto entanglement takes place.
 OHE defects and Pantograph defects are few reasons of Pantograph
entanglement.

RDSO, Lucknow 39
Reference:
 www.rdso.indianrailways.gov.in
 www.scribd.com/
 http://www.rdso.indianrailways.gov.in/works/uploads/File/Maintenanc
e%20schedule%20for%20diesel%20electric%20type%208%20wheel
er%20tower%20wagon(2).pdf
 www.irieen.indianrailways.gov.in
 https://www.railelectrica.com/traction-distribution/25kv-power-supply-
system/
 https://en.wikipedia.org/wiki/OHE
 Kaba H, Shiraishi S, Yagi N, Onda S. Development of a high
efficiency traction system, J-RAIL2005, 469–472 (in Japanese), 2006.

RDSO (Indian Railways) Industrial Training Report

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